Heterologous laccase production and its role in industrial applications

Laccases are blue multicopper oxidases, catalyzing the oxidation of an array of aromatic substrates concomitantly with the reduction of molecular oxygen to water. These enzymes are implicated in a variety of biological activities. Most of the laccases studied thus far are of fungal origin. The large range of substrates oxidized by laccases has raised interest in using them within different industrial fields, such as pulp delignification, textile dye bleaching and bioremediation. Laccases secreted from native sources are usually not suitable for large-scale purposes, mainly due to low production yields and high cost of preparation/purification procedures. Heterologous expression may provide higher enzyme yields and may permit to produce laccases with desired properties (such as different substrate specificities, or improved stabilities) for industrial applications. This review surveys researches on heterologous laccase expression focusing on the pivotal role played by recombinant systems towards the development of robust tools for greening modern industry

Identification of laccase-like genes in ectomycorrhizal basidiomycetes and transcriptional regulation by nitrogen in Piloderma byssinum

Ectomycorrhizal (ECM) fungi were screened for laccase-like genes by polymerase chain reaction (PCR) using primers for white rot fungal laccase genes, and expression of the genes was examined by reverse transcriptase polymerase chain reaction (RT-PCR) for Piloderma byssinum in axenic culture under different nutrient conditions. Laccase-like genes were present in Rhizopogon roseolus along with several Russulales and Atheliaceae taxa, and showed strong nucleotide sequence similarity to laccase genes in white rot fungi. Multiple laccase-like genes were only identified in Piloderma spp. Laccase-like genes were expressed in Piloderma spp., with transcript levels some six times higher under high nitrogen conditions in P. byssinum than when nitrogen availability was lower. The potential roles of laccases in nutrient mobilization and/or differentiation of multihyphal ECM fungal structures are discussed